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EWG's Tap Water Database — 2021 UPDATE

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Monochlorobenzene (chlorobenzene)

City of San Marcos

Monochlorobenzene is used as a solvent for pesticides, a degreasing agent and an intermediate for manufacturing other chemicals. It causes liver and kidney damage in studies of laboratory animals.

 

36

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND50ND
2015ND60ND
2016ND60ND
2017ND70ND
2018ND60ND
2019ND60ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 70 ppb

The EWG Health Guideline of 70 ppb for monochlorobenzene was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against harm to internal organs.

EPA Maximum Contaminant
Level (MCL) 100 ppb

The legal limit for monochlorobenzene, established in 1991, was based on a toxicity study in laboratory animals conducted in the 1960s.

ppb = parts per billion

All test results

Date Lab ID Result
2014-03-12AC63077ND
2014-08-12AC63071ND
2014-08-12AC63073ND
2014-08-12AC63087ND
2014-08-12AC63075ND
2015-06-10AC95472ND
2015-06-10AC95470ND
2015-06-10AC95474ND
2015-06-10AC95468ND
2015-09-23AD08299ND
2015-09-23AD08303ND
2016-03-16AD29111ND
2016-09-16AD49839ND
2016-11-28AD59222ND
2016-11-28AD59220ND
2016-12-12AD61688ND
2016-12-12AD61664ND
2017-02-22AD71534ND
2017-05-03AD82464ND
2017-05-03AD82462ND
2017-05-03AD82466ND
2017-05-03AD82468ND
2017-07-12AD89095ND
2017-10-12AE00574ND
2018-01-25AE10638ND
2018-01-25AE10564ND
2018-01-25AE10572ND
2018-01-25AE10574ND
2018-04-11AE22067ND
2018-07-26AE34698ND
2019-01-16AE50162ND
2019-01-16AE50166ND
2019-01-16AE50168ND
2019-01-16AE50164ND
2019-04-16AE62552ND
2019-07-09AE73687ND